SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f96a00edf38d08f031968f205f85b64ec47b94102089e9b8af3dec1f55fa9ff' 
  AND token = 'LuNkCEM/SJ81IMHt27P36GGVHMe6Owu6MgAoyE3slRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}